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50 Cards in this Set

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  • Back
What is Ecosystem
sum total of all organisms and abiotic factors in a particular enviroment
What is the portion of an ecosystem where a community could reside ?
An ecosystem contains many different __________
Habitat.
Also Habitat
What is the term for the total number of different species present?
species richness
What is the term for the proportion of each species in an ecosystem?
species abundance
Microbial species richness and abundance is dependant on .....
the type and amount of nutrients available in a given habitat
What is a guild?
a group of microbial populations that has the same metabolic function
Sets of guilds produce ____________ that interact with macroorganisms and abiotic factors in the ecosystem
microbial communities
What is a niche?
What does a niche supply the organisms
A Habitat shared by a guild
supplies nutirents and conditions
The immediate enviromental surroundings of a microbial cell or groups of cells is called a _________________
Microenvironment
A grain of sand shows different niches. How ?
each layer has a different niche because each has its own metabolic activity
Why are surfaces important microbial habitats ?
Nutrients adsorb to surfaces

Microbial cells can attach to surfaces
What are biofilms are where do they come from ? Why are they useful?
an adhesive poly saccharide matrix that is used to enclose cells. Excreted by the cells
Biofilms trap nutrients for microbial growth and help prevent detachment of cells in flowing systems
What do cell in biofilms tend to be to each other
symbionts
The three steps for making a good biofilm ?
Attachment - free floating usually motile cells go to a surface and attach to it. Their flagella falls off
Colonization - The polysaccharides matrix is formed, and their is intracellular communication growth.
Development - the number of cells and polysaccharides film grows. Some cells slough off and become motile again when the bio film gets old. Holes made for water channels
Very thick biofilms that are visible to the eye are called what ?
Microbial mats
Microbial mats made by which bacteria. What do each contain
Phototrophic and / or chemolithotrophic bacteria

Phototrophic - contain filamentous cynobacteria
Chemolithotrophic - contain filamentous sulfur oxidizing bacteria
What is a Winogradsky column? What does it show ? Why are winogradsky columns considered stable ?
Its a cross section of a microbial mat
cyno bacteria mat on the top, Purple is anoxygenic sulfur oxidizing bacteria the bottom is black , sulfur reducing

They are very stable because the guilds are complementary to each other because one eats the products of the others and so on and so forth
What is the outer material on the earth's surface
Soil
What groups can soils be divided into? Describe each
Mineral soils
Derived from rock weathering and other inorganic materials

Organic soils
Derived from sedimentation in bogs and marshes
Which horizon do decomposers love the most ?
the O horizon
Soils are composed of. From highest to lowest matter
50% air and water
40% of inorganic soil volume
5% organic matter
Where does most microbial growth take place
surface of soil particles
What is the most important factor influencing microbial activity in surface soil
What is the most important factor for for subsurface enviroments?
WATER
nutrients
how do microorganisms in the deep subsurface have access to nutrients ?
because of groundwater flow
What are oxygenic phototrophs suspended freely in water; include algae and cyanobacteria
Phytoplankton
What are attached to the bottom or sides of a lake or stream
Benthic species
What is a thermocline
its where everything changes in a lake .
How can fresh water rivers suffer oxygen deficiencies ?
Organic matter from sewage

Agricultural and industrial pollution
Compared to fresh water, open ocean environment is?
Saline

Low in nutrients, especially with respect to nitrogen, phosphorus, and iron

Cooler
In order to survive the saline conditions, the bateria mus be
Halo tolerant
why do near shore marine waters typically contain higher microbial numbers?
because nutrients are pushed to the shhore and stay there
what are prochlorophytes?
Prochlorococcus accounts for how much the biomass of marine phototrophs and how much of the net primary production
Most of the primary productivity in the open oceans is due to photosynthesis
40% of the biomass of marine phototrophs
and 50% of the net primary production
The planktonic filamentous cyanobacterium ____________ is an abundant phototroph in tropical and subtropical oceans
Trichodesmium <===adapted to high temperature
Small phototrophic eukaryotes, such as ____________, inhabit coastal and marine waters and are likely important primary producers
Ostreococcus
What is abundant in pelagic marine waters?
Small planktonic heterotrophic prokaryotes
What densities of bacteria decrease with depth?
Prokaryotic densities
Why do densities decrease with depth?
Less resources
What type of organisms dominate the surface waters and which dominate the deeper waters?a
Surface waters- bacterial species, Deeper waters- Archaeal species
Why are archaea more abundant in deeper waters?
They are more adapted
What is an oligotroph?
An organism that grows best at very low nutrient concentrations
What is the most abundant marine heterotroph?
Pelagibacter
What is proteorhodopsin and what does it do?
A form of rhodopsin that allows cells to use light energy to drive ATP sythesis
Why are heterotrophs with proteorhodopsin not considered true phototrophs?
Because it does not use photosystem one or two--> instead it uses sun directly
What are the most abundant microorganisms in the oceans?
Viruses
What is biogeochemical cycling?
The linked cycling of all nutrients in the environment (on Earth) and this includes both biogocial and chemical processes and are reducing and oxidizing at all times
What kind of processes do aerobic carbon users do?
Oxidizing
What kind of processes do anaerobic carbon users do?
Reducing
How do acetogens make their food?
Use H2 and CO2 to make acetate
What do acetogens have to compete with for food?
Methanogens
What can fix nitrogen?
ONLY bacteria